129,404 research outputs found

    Power filters for gravitational wave bursts: network operation for source position estimation

    Full text link
    A method is presented to generalize the power detectors for short bursts of gravitational waves that have been developed for single interferometers so that they can optimally process data from a network of interferometers. The performances of this method for the estimation of the position of the source are studied using numerical simulations.Comment: To appear in the proceedings of GWDAW 2002 (Classical and Quantum Gravity, Special issue

    Kinetics of the reaction OH (v equals 0) plus O3 yields HO2 plus O2

    Get PDF
    The rate constant (kl) of the reaction OH(v=o) + O3 yields HO2 + O2 measured over the temperature range 220 to 450 K at total pressures between 2 and 5 torr using ultraviolet fluorescent scattering for the detection of OH radicals. An Arrhenius expression was obtained, and the rate constant for the reaction HO2 + O3 yields OH + 2O2 was inferred to be less than 0.1 kl over the entire temperature interval

    Gender Equity in Intercollegiate Athletics: Determinants of Title IX Compliance

    Get PDF
    Using new data on intercollegiate athletes, this article shows that recent improvement in Title IX compliance among NCAA Division I institutions was previously overestimated, and provides the first estimates of compliance in Divisions II and III. In addition, regression analyses investigate how institutional characteristics relate to the extent of non-compliance

    A Mission to Test the Pioneer Anomaly

    Full text link
    Analysis of the radio tracking data from the Pioneer 10/11 spacecraft has consistently indicated the presence of an anomalous small Doppler frequency drift. The drift can be interpreted as being due to a constant acceleration of a_P= (8.74 +/- 1.33) x 10^{-8} cm/s^2 directed towards the Sun. Although it is suspected that there is a systematic origin to the effect, none has been found. The nature of this anomaly has become of growing interest in the fields of relativistic cosmology, astro- and gravitational physics as well as in the areas of spacecraft design and high-precision navigation. We present a concept for a designated deep-space mission to test the discovered anomaly. A number of critical requirements and design considerations for such a mission are outlined and addressed.Comment: Final changes for publication. Honorable Mention, 2002 Gravity Research Foundation Essay

    Has the long-run velocity of M2 shifted? Evidence from the P* model

    Get PDF
    An examination of one of the P-Star model's primary assumptions: the constancy of M2's long-run velocity, or V-Star. Using actual data through the end of 1992, the authors find that simulations of the model under a variety of hypotheses regarding changes in V-Star provide little support for a dramatic shift in that measure.Inflation (Finance) ; Money supply ; Velocity of money

    Design considerations for the airframe-integrated scramjet

    Get PDF
    Research programs at the NASA Langley Research Center on the development of airframe-integrated scramjet concepts (supersonic combustion ramjet) are reviewed briefly. The design and performance of a specific scramjet configuration are examined analytically by use of recently developed and substantiated techniques on boundary-layer development, heat transfer, fuel-air mixing, heat-release rates, and engine-cycle analysis. These studies indicate that the fixed-geometry scramjet module will provide practical levels of thrust performance with low cooling requirements. Areas which need particular emphasis in further development work are the combustor design for low speeds and the integrated nozzle design

    Developing the Spatial Dimension of Farm Business Models

    Get PDF
    A non-linear mathematical farm business optimisation model, that is set within a spatial economic framework, has been developed. The model incorporates factors such as location, spatial market orientation and technology use, and identifies the business strategy that is optimal in different market and policy environments. Farm household time-use is incorporated centrally within the model, enabling it to examine how on-farm and off-farm activities compete for limited farm household human resources. The model is applied to a beef and sheep farm that can choose between selling livestock to meat processors or processing on-farm and selling direct to consumers. Model simulations reveal when it is optimal for the farm business to innovate in this way and how this decision is affected by changes in key parameters. The farm business model is solved using the GAMS/LINDOGlobal mathematical programming software package. While traditional nonlinear programming and mixed-integer nonlinear programming algorithms are guaranteed to converge only under certain convexity assumptions, GAMS/LINDOGlobal finds guaranteed globally optimal solutions to general nonlinear problems. The model and model results are discussed within the context of theoretical underpinnings, model tractability, and potential applications.Farm Management,

    In situ observations of BrO over Antarctica: ER-2 aircraft results from 54 S to 72 S latitude

    Get PDF
    Bromine monoxide was observed in situ at approximately 18 km altitude during nine flights of the NASA ER-2 aircraft from Punta Arenas, Chile (54 altitude) to 72 S latitude over the Palmer Peninsula, Antarctica. The first flight for the BrO detection system was on 28 August. Here, the results from the flights over Antarctica and from the ferry flights from Punta Arenas to Moffett Field, CA (37 N latitude are reported. A key question concerning BrO, then, is how it is distributed with respect to the chemical containment vessel defined by elevated ClO mixing ratios. This question is answered with greatest statistical significance if the data are averaged into five regions: outside the vessel, aircraft heading south; inside the vessel on the same potential temperature surface; in the dive region; inside the vessel on a given potential temperature surface, aircraft heading north; and outside the vessel on the same surface. The result is that the BrO distribution inside the chemical containment vessel was different from that found outside. Inside, the BrO mixing ratio was (5.0 plus or minus 1.1) pptv between the 400 K and 460 K potential temperature surfaces, decreasing only slightly with potential temperature, and was less than 3.6 pptv below the 4 00 K surface. The abundance of BrO inside the chemical containment vessel showed no discernible temporal trend during the course of the nine flights. Outside the vessel, the BrO mixing ratio was (4.7 plus or minus 1.3) pptv near the 450 K surface, but decreased to (2.8 plus or minus 1.0) pptv near the 420 K surface

    Baffling of fluid sloshing in cylindrical tanks Final report

    Get PDF
    Annular baffle for damping liquid oscillations in partially filled cylindrical tan

    Parametric analysis of diffuser requirements for high expansion ratio space engine

    Get PDF
    A supersonic diffuser ejector design computer program was developed. Using empirically modified one dimensional flow methods the diffuser ejector geometry is specified by the code. The design code results for calculations up to the end of the diffuser second throat were verified. Diffuser requirements for sea level testing of high expansion ratio space engines were defined. The feasibility of an ejector system using two commonly available turbojet engines feeding two variable area ratio ejectors was demonstrated
    • …
    corecore